A kinetic model for olefin polymerization in high-pressure autoclave reactors

Free radical copolymerization in high‐pressure autoclave reactors is studied by developing a mathematical model. Kinetic mechanisms to describe the polymerization rate, molecular weight averages, branching frequencies, as well as copolymer composition are presented. Two phase kinetics due to polymer‐monomer solubilities in the reaction mixture are taken into account. Gel formation from cross‐linking reactions is also analyzed. A mixing model is developed to represent the stirring effect inside the reactor. The mathematical model is implemented as a computer program to simulate commercial autoclave reactors. PID control equations are used to maintain operation at the unstable steady state. A sensitivity study is performed on the mixing model parameters and on some of the kinetic parameters and the model is compared to rate data from commercial reactors.